Automatic induction relay



June 12, 1934. M. A. WALKER 1,962,795

AUTOMATIC INDUCTION RELAY Filed April 15, 1950 7 /.9 T ZO/T Z5 24 A A A 2/ N22 O J{JU a i W l W735i m h lfw Patented June 12, 1934 UNITED STATES PATENT OFFICE 1 Claim.

The invention is an induction relay, and has special reference to an automatically operated switch for controlling various electrical circuits and devices.

The main object of the invention is to provide an automatic contactless and sparkless electric relay. I

Another object of the invention is to provide a device as specified which may be used to automatically control various heating, pumping and other devices.

A further object of the invention is to provide a device as outlined above which may be operated by means of liquid or gas pressure, by means of floats or other means, thereby providing automatic operation.

Other objects of the invention will become apparent as the description is set forth in conjunction with the drawing.

The invention consists primarily of a movable core transformer, the core comprising substantially a piston, and slidable within a cylinder of non-magnetic material, primary and secondary coils spacedly disposed on the cylinder relative to the longitudinal axis, the core normally extending through the primary coil and moved within the secondary coil by liquid pressure or other cooperating means.

Referring to the accompanying drawing Fig. 1 is a sectional view through the device;

Fig. 2 is a wiring diagram of the invention;

Similar reference characters are used to designate similar parts throughout the several views.

The invention consists of a primary coil 3 and a secondary coil 4 wound about a nonmagnetic sleeve 5 with a laminated magnetic core 6 slidable therein, and which is normally in the relative position indicated in the drawing, Fig. 1.

The device is best illustrated as to application in Figs. 1 and 2, although various other methods of actuation are possible, and adaptable to the invention. In Fig. 1 a water supply pipe 7 is threadedly connected to the sleeve 5, the normal flow of the water through the pipe being upward.

Sleeve 5 is made of a non-magnetic material such as brass, and is provided with interior projections 8 on which the core 6 is adapted to rest. A side outlet 9 is disposed above the projections 8, whereby the side outlet 9 is normally sub stantially closed by the core 6. An elbow 10* is provided with a depending stop 11 to limit the upward movement of the core, so as to prevent its movement out of the primary coil 3, the elbow 10 being in circuit with a nipple 12, T

13 and valve 14. A bypass is provided from the side outlet 9 through the street L 15, nipple 16, union 17 and nipple 13 to the T 13. An alternating current supply is connected in circuit with the terminals 19 and 20 of the primary winding, the output being connected to the terminals 21 and 22 of the secondary winding.

The wiring diagram illustrates the principle in two forms, indicating that for operation the secondary is always in closed circuit with an electrical device, a lamp 25 and relay 29 being indicated, although the connections can as readily be made to a motor, heating device. or other appliance.

In normal position as indicated in the drawing, the primary coil 3 is provided with a magnetic core 6 while the secondary coil 4 has an air core. Primary coil 3 together with magnetic core 6 acts as the primary circuit of a transformer, and very little current flow is induced in the secondary coil.

Should the valve 14 be opened, a difference of pressure is created between the valve 14 and pipe '7 whereby the core 6 is raised to a position linking the magnetic circuit of the primary and secondary coils and inducing a current in the secondary coil 4. When the valve 14 is closed the pressure is equalized between the valve 14 and pipe 7 permitting the core6 to drop to the normal position, reducing the induced E. M. F. in the secondary to a low value.

In Fig. 2, an alternating current power supply line is indicated at 27 and 28 with a double pole single throw switch 26 in circuit with the primary winding 3 and a magnetic core 6 within the primary coil, the alternating current causing an alternating magnetic flux which sets up a counter E. M. F. equal to the primary E. M. F. plus an E. M. F. in the secondary 4 due to mutual inductance between the coils 3 and 4, the only current then flowing being that necessary for magnetizing current to set up the flux in the magnetic circuit, plus losses due to hysteresis and eddy-currents and a small amount due to mutual inductance between the coils.

When the core 6 is raised within the secondary, the load on the primary increases and due to the permeability of the iron core an increased current is induced in the secondary, which maybe used to light lamps 25 which are connected across the terminals 21 and 22 by wires 23 and 24, or by use of a relay 29 connected across the terminals 21 and 22 a second circuit may be closed.

The secondary of the properly designed transformer may readily be connected directly in circuit with water heaters, motors, solenoids, or other electrical apparatus, and the core may be operated as indicated in the drawing or by means of a float in a tank of liquid, by air pressure or by vacuum.

It will be noted that variations in design, construction and arrangement of parts which are consistent with the appended claim may be resorted to without detracting from the spirit or scope of the invention or sacrificing any of the advantages thereof.

I am aware that movable core transformers have been made, therefore I do not claim such a combination broadly, but I do claim:

An induction relay comprising a vertical, nonmagnetic cylinder open at its top and bottom, a magnetic core within the cylinder, said cylinder having a core seat formed adjacent the bottom thereof, abypass communicating with the top and the bottom of the cylinder, the lower end of the by-pass being above the seat, said magnetic core slidable within the cylinder and normally resting on the seat and closing the bypass, a discharge outlet communicating with the by-pass, a valve in said outlet, a primary winding on said core and a secondary winding on said core and spaced from the primary winding for linking the magnetic fields of the primary and secondary coils when the core is moved upwardly in the cylinder.

MILTON A. WALKER. 

